16 September 2009

How's my RTPJ?

Have you always been aware of the beliefs of others or did you just grow that way?

With an inhibited Right Temporo-Parietal Junction (RTPJ) would you struggle to understand that others can have beliefs different to yours? Would this inhibition cloud your ability to make moral judgements? Current neuroscientific research using fMRI suggests increased activity in this small brain region when volunteers are tasked with thinking about various situations from the point of view of another human being.Studies by Rebecca Saxe and others see the RTPJ as being key to the morality aspects central to a cohesive "theory-of-mind". Her studies have found that the abilities of children to reason out and judge scenarios of "people thinking about thinking people" develop markedly and rapidly between the ages of approximately three and seven years old.

An example would be where a child, with the aid of props, was asked to envision a man putting a sandwich down on a box. The man then leaves and the sandwich gets blown off the box by the wind. A second man comes along and puts his sandwich down on the box, not seeing the one on the ground, then leaves. The child, once given the scenario, is asked which sandwich the first man will take when he returns. According to the Saxe studies the children would respond thus:

The 3-year-old says that the first man will take the sandwich on the ground although it is dirty because it is "his". When told that the first man actually takes the one on the box the child expresses surprise - presumably meaning that she cannot understand that the first man would not know that his was the one on the ground, so she thinks it unfair that he took the one on the box.

The 5-year-old says that the first man will take the sandwich on the box. This appears to show a more developed understanding of the thoughts of others because the child understands that the first man would think (albeit mistakenly) that his sandwich was the one on the box. However, the 5-year-old, still says that it is "bad" of the first man to take the sandwich on the box. Is this evidence that the child has not yet developed the moral capacity to know that the first man cannot be blamed for not knowing he was mistaken?

The 7-year-old says that the first man will take the sandwich on the box. Crucially, she also knows that the first man should take no blame for his mistake because it was a simple accident/misunderstanding.

This is a rather wordy explanation and you can see the Saxe talk on ted.com which should make it all clearer. She also brings up the fascinating results of studies, in adult subjects, where the RTPJ is stimulated (through the skull) via electromagnets. This appears to demonstrate a decreased ability in the subjects to make usual moral judgements while the RTPJ's function is being disrupted.

Other work, such as that of JP Mitchell does not appear to directly contradict the Saxe papers but does, again, bring up the issue of "localisation". He appears to be saying there is no current conclusive proof that the RTPJ is solely responsible for this kind of reasoning, despite the fact it lights up under fMRI when these judgement tasks are undertaken.

It must be very tempting for neuroscientists to fit specific cognitive functions to specific brain regions, especially now that fMRI studies seem to corroborate some of these theories. It's also much easier to explain to laypeople than telling them that fMRI studies suggest increased blood flow in areas that might be associated with a particular function when subjects undertake cognitive tasks that might stimulate blood flow to the region in question. While the "localisations" may be broadly correct there seems to be a bit too much "shoehorning" going on in some of these studies.

There are, of course, ethical issues connected to the potential ability to disrupt a person's ability to make reasoned moral judgements; or to actually change their beliefs by electro-mechanical means! This ability doesn't appear to be on the horizon any time soon. I have no fear of and can see a lot of value in this kind of work and, unlike Ms Saxe, I do think that this will help us to understand "the hard problem" of consciousness.

This is me signing off thinking about me thinking about you thinking about your beliefs about how you think about the thoughts of thinking people.